Omron CJ - 09-2009 Operation Manual page 52

CJ-series Features
Program and PLC Setup
Compatibility with CS-
series CPU Units
No Backplanes for Greater
Space Efficiency
Up to 3 Expansion Racks
and 40 Units
Two I/O Allocation
Methods
Allocate Unused Words
Structured Programming
Division of the Program
into Tasks
4
There is almost 100% compatibility with CS-series CPU Units for program-
ming and internal settings (PLC Setup).
Note Because of physical differences in the CJ-series PLCs, they do not
support all of the features of the CS-series PLC.
A flexible system configuration that requires less space is made possible
because Backplanes are not required for CJ-series PLCs.
By connecting an I/O Control Unit to the CPU Rack and I/O Interface Units to
Expansion Racks, up to three Expansion Racks (but only one for CJ1M CPU
Units) can be connected. The CPU Rack can contain up to 10 Units, as can
each of the three Expansion Racks, enabling a total of up to 40 Units.
The need for Backplanes was eliminated, enabling the following two methods
for allocating I/O.
1. Automatic I/O Allocation at Startup
I/O is allocated to the connected Units each time the power is turned ON
(same as CQM1H PLCs).
2. User-set I/O Allocation
If desired, the user can set I/O tables in the same way as for the CS-series
PLCs.
The default setting is for automatic I/O allocation at startup, but the user can
set the PLC to automatically use I/O tables to enable checking for Unit con-
nection errors or to allocate unused words.
The CX-Programmer can be used to allocate unused words in I/O tables for
transfer to the CPU Unit. This enables keeping words unallocated for future
use or to enable system standardization/modularization.
When the program is divided into tasks that handle separate functions, control
systems, or processes, several programmers can develop these separate
tasks simultaneously.
There can be up to 32 normal (cyclic) tasks and 256 interrupt tasks. There are
four types of interrupts: the Power OFF Interrupt, Scheduled Interrupts, I/O
Interrupts, and External Interrupts (interrupts from Special I/O Units or CPU
Bus Units).
Earlier program
When a new program is being created, standard programs can be combined
as tasks to create an entire program.
Section 1-2
Task
Task
Task
Task